Grim Adventures of Billy and RWBY
by Marka Ragnos629
Summary: Billy is sent to the world of RWBY to fight and end an ancient war, and perhaps find love along the way. What could possibly go wrong? Billy x Harem! Arkos!
1. Chapter 1

_**I actually got this idea when I remembered a certain episode from this series and decided to give it a go. If people like it, I'll continue. And if they don't? Well, it was fun while it lasted. All I ask is that you give it a chance and keep an open mind.**_

 _ ***I don't own Grim Adventures of Billy and Mandy, or RWBY!***_

* * *

 _ **Dialogue Key**_

* * *

"Behold, the Accursed Armor of the Black Knight!" = Regular Speech

 _'Why is it accursed?' = Thoughts_

 **"Hey. Hey, what's going on? I can't get the suit off!" = Someone Yelling**

 _ **"** **Oh, that's why." = Spirits Speaking**_

* * *

 _ **Experimental Prologue**_

* * *

In the haunted town of Endsville, a young man was walking home from a long and emotionally tiring day at high school. This young man has a lightly tanned skin tone, reddish orange hair, and brown eyes that have the appearance of just being holes in his face. He also has a ridiculously big pink honker that he calls a nose. The young man is currently wearing his school uniform, a white dress shirt left untucked, blue pants, and a pair of red and white sneakers. What sets him apart from the other kids, however, is the dark red baseball cap he's often seen wearing on his head.

"Ugh, what a day this has been. Spurg really needs to learn how to lighten up when it comes to his bullying. I mean, really! Wedgies, no problem, can easily be cured with medical salve and a change of underwear. Wet willies? Had them, easy to dry and disinfect with tissues and a cotton swab. Being stuffed in my own locker for hours on end? Not too bad, the janitor always lets me out before I'm late for history class. But cornering me outside the school and slashing me across the chest with a knife during lunch just to steal my money!? WHAT HAS THIS WORLD COME TO!?" the boy said to himself, shouting his question at the end.

This boy is simply called Billy, and he's seventeen years old now and in high school. Though, unlike his father, he doesn't go around trying to be popular when he's not. And unlike his highly obese father, Billy is built more like an olympic runner after having decided to take his diet and exercise more seriously. Much to the surprise of those who knew him. As a result, he's built with lean and compact muscles and is obviously tall for his age, standing at six feet seven inches tall. He's certainly not overly muscular, and he does have a noticeable six-pack of abs. If not for that schnoz he'd be getting looks from all the ladies.

But more to the point, he's referring to earlier at lunch where the school bully and local juvenile delinquent, Spurg, and his gang cornered Billy outside the cafeteria at lunch and attacked him for his money. Spurg pulled out a pocket knife he'd kept hidden on his person and slashed Billy across the chest, cutting deep and causing Billy to need to see the nurse. Thankfully, the wound was easy for the nurse to sew up and as long as he took it easy for a little while, he'd be fine.

Spurg and his flunkies, on the other hand, had been arrested for charges of attempted murder, theft, and unprovoked assault. And those are just a few of the charges. And now, Billy is walking home to recover after school let out. He arrived in less time than he thought it would take with the injuries he sustained.

Upon entering his house, Billy made his way to the stairs that lead up to the upper level where his room is located. He just wants to get some sleep and try to forget this whole rotten day. But as he was passing the kitchen, he heard something.

"...I think it might be best for Billy." said a woman's voice.

One that Billy easily recognized and caused him to stop in his tracks.

"That sounds like mom." Billy said to himself.

He peeked into the kitchen and saw that his mom was sitting at the dining room table with his dad. Both were nursing cooling cups of coffee in their hands and looked like they were having a serious conversation. And from what Billy caught earlier, it was about him.

Billy's dad, Harold, looks an awful lot like he does, only he has black hair instead of being a redhead and is quite fat. Ninety seven percent fat, one might say. And his mother, Gladys, is the one who Billy gets his hair color from. If there's one thing someone can say about Billy's mom, it's that she's the absolute picture of a stereotypical housewife.

But, back to their conversation.

"I don't know, honey. I mean, I know that our son doesn't have the best of lives here in Endsville, especially with what the school called us about today, but do you really think just up and moving is the only solution there is? And enrolling him in military school of all things!? Why that!?" Harold asked.

"Harold, listen! It's just not safe for anyone to be living in Endsville anymore! What happened to Billy today is a perfect example of that! So I say we should move away from this wretched town and live someplace safer! Sure, he's got friends like Irwin who still live here in Endsville, and I know he might miss them for a little bit, but Billy's a big boy! He'll get over it!" Gladys exclaimed. ' _And keep my son as far away from that blonde harlot and that cursed skeleton as physically possible!'_

"And the part about enrolling him in military school? What's that part all about?" Harold asked.

"Billy's obviously quite physically fit, but he lacks much of the discipline that a person needs to be a successful adult like you are. And the only way to get that is with military training. I'm enrolling him tomorrow morning, and that's that!" Gladys exclaimed.

But unknown to her, Billy heard the entire one sided conversation and snuck up to his room to pack. There's no way he's staying in this house if he's going to be forced to leave Endsville and all his friends behind. Even though he and Mandy aren't really friends anymore. He packed up his clothes, he packed tools, his toothbrush, a tube of toothpaste, his collection of Dinobonoids, even a whole ham he had stashed away in there!

He cleaned out that closet as quick as a flash, and hid his suitcase in the one place in his room that nobody would think to look for it. Behind the very same wall that Mandy had kept him sealed behind when her house was being fumigated due to his stink bomb. Which, now that he thinks about it, wasn't one of his better creations. He could have at least left out the raw sewage.

' _I'll leave when mom and dad are asleep tonight. It won't be hard for me to just walk out of the house and leave for good, because those two sleep like bears in hibernation.'_ Billy thought to himself in one of those rare times his brain is actually in use.

And so, Billy got ready. For tonight, he's embarking on a journey the likes of which not even the Grim Reaper himself could send him on.

* * *

 _ ***To Be Continued…***_

* * *

 _ **So, what did you guys think? Is this story worth continuing? Or should I let someone else write it? Let me know what you think.**_


	2. Chapter 2

_***I still don't own Grim Adventures of Billy and Mandy, or RWBY!***_

* * *

 _ **Dialogue Key**_

* * *

"Behold, the Accursed Armor of the Black Knight!" = Regular Speech

 _'Why is it accursed?' = Thoughts_

 **"Hey. Hey, what's going on? I can't get the suit off!" = Someone Yelling**

 _ **"Oh, that's why." = Spirits Speaking**_

* * *

 _ **Leaving One World For A New One**_

* * *

In the realm of spirits, a plane between dimensions, there were two spirits that were currently conversing as they looked at a certain boy who was currently going over a check list before he made his escape. Both of them are warriors who are the spirits of two certain items that Billy used for a brief time in the past. Of course, it may not have been for combat, but he still did so.

The first of these warriors in a man who is in his early forties, maybe forty three, who has a muscular build that's much greater than Billy's. He's obviously built for power over speed, but that doesn't mean he's slow. He has long black hair pulled into a low warrior's wolf tail that is greying on the sides, a goatee, and naturally pale skin. His eyes are quite narrow and almond shaped, giving him the appearance of almost constantly squinting, and is currently dressed in armor that is a layer of dark gray chainmail with black armor plating over it. This armor includes a chestplate, a pair of gauntlets, gloves, and greaves, metal shoes, and a pair of pauldrons.

This spirit is known as Kuroryu, the spirit of the Accursed Armor of the Black Knight.

The second spirit is also a man, but he looks more like a samurai of ancient Japan than a knight. He wears a black yukata over samurai style pants, white geta sandals, and bandage wrapping around his forearms. Strapped to his hip is a very familiar sword that Billy has attempted to use in the past, and his head and facial features are obscured by the tattered white hooded cowl he's wearing.

This man is the spirit of the Accursed Sword of the Black Knight.

Both of them have been watching over young Billy ever since they first met him as a child all those years ago at that strange festival. Though, in the sword's case, Billy never really got a chance to use him due to the blade being too heavy for his younger and less athletic body. But now that he's older, he'll be able to utilize his power to its fullest so that he may take up this mission that he has been chosen for.

" _ **Are you certain that he is the one?"**_ asked the sword spirit, having a few doubts about Billy.

And with good reason. The lad's never seen true combat before, and even though he's helped stop threats like the boogeyman, he's never done any of the actual fighting. If anything, he's just been the comedic relief of the group while Mandy, Grim, and even Irwin did all of the real fighting. But the boy is durable, the sword spirit will give him that much.

The armor spirit didn't even need to contemplate as he spoke in a gruff voice with an accent that sounded like a knight from the days of medieval Britain.

" _ **Verily. The lad dost possess the heart of a warrior, and so he hath been chosen to become one. A dark future approacheth a distant universe, and so the gods have seen fit to select a champion to prevent this cataclysm."**_

" _ **Well, he may have passed your test, Armor, but until he passes mine he's not using me in a fight."**_ said Sword. " _ **Now let's hurry up and get to this guy so we can leave."**_

Let it be known that until you've earned the respect of the Accursed Sword of the Black Knight, he'll be quite rude and impatient with whoever is trying to use him in a fight. This of course made the spirit of the armor roll his eyes at his companion's behavior. Honestly, why does he have to make such a big deal out of everything. So what if things could possibly go wrong in entrusting the fate of the entire multiverse to a single human teenager? What's life without a little adventure?

With a snap of their fingers, the spirits of the two medieval weapons vanished from the spirit world to find Billy and get him started on his mission.

* * *

Later that night at exactly one o'clock in the morning, Billy was seen walking to the ends of Endsville so he could escape from his controlling mother, who seems to only want to control his life and make sure he had no say in his path in life. He had his suitcase in hand with all of his supplies at the ready.

He just hoped that his friends understood why he left like he did. Especially without saying goodbye in person.

Before he left forever, Billy left several letters to each of his friends in the nearest postbox so that they'd be mailed out to all of them come the morn. Two for each of them. One that would give them his parting words, and another that would detail exactly what he's had to put up with in these more recent years of his life. Especially Mandy, to whom he wrote down some pretty choice words. Words that I shall not be describing at this moment in time.

As he neared the border to the town, Billy took one final look at the place he grew up in for just about his whole life. The town that holds so many wonderful memories for him.

"Goodbye, Endsville. Hopefully, when I come back, I'll be a stronger and better person." Billy said, more to himself than the actual town.

" _ **We happen to know a way that you could accomplish this goal of yours, young man."**_

Billy gasped and took a few steps back as twin pillars of fire erupted in front of him. He watched in fascination as the flames died down to reveal the two spirits from earlier. Only this time, they were holding their respective artifacts in their arms. Both looked impassive, but also looked at Billy as if expecting him to do something. Something involving their entrance.

"Cool entrance, guys. But I think you shouldn't have made the heat from your flames so high. I swear I got a tan from that." Billy quipped.

" _ **Wait. So, you're not freaked out by us just magically popping out of twin pillars of fire? That doesn't freak you out in the slightest?"**_ asked the sword spirit.

"Nope. I'm so used to the supernatural that things like this just don't faze me anymore." Billy replied.

" _ **Well, now we're just embarrassed. We chose to come before you in a flashy manner, hoping to get you to start screaming like a girl, like you normally do, and yet you don't even bat an eye. You, my boy, have just begun to earn my respect."**_ said the sword spirit.

"Uh, that's very kind of you to say, sir. But who are you guys? I feel like I've seen you somewhere before." Billy asked.

The spirit in armor gave a deep, boisterous laugh at what Billy just said. Despite not using his brain very often, he seems to never forget a supernatural presence. Even if it's one he's only ever felt one time and only sensed that presence years ago.

" _ **Well, you catch on quick, young Squire! Thou shouldst know us, for thou hast utilized our powers for a brief time, many years ago."**_

The armored spirit's words seemed to confuse the young man. What did he mean when he said that he used them both years ago. Billy thought back to his childhood as he attempted to remember any kind of supernatural artifacts he may have used in the past. There was that time traveling TV remote, he used Grim's scythe for a little bit, and then there was that wishing skull. Wait a minute…

That armor and sword definitely look familiar. Billy gasped as he finally remembered what they were.

"That's why I recognize you two! You're that black knight armor and sword!" exclaimed Billy.

" _ **Ding ding ding! Give the lad a prize!"**_ the sword spirit exclaimed. " _ **You're absolutely correct, Billy. I am the Spirit of the Accursed Sword of the Black Knight, and he is the Spirit of the Accursed Armor of the Black Knight. Nice to meet you in person, lad."**_

"But how is this possible!? I thought you guys were gone after that day!?" Billy asked, almost shouting at this point.

" _ **True, you did defeat someone in a challenge and were able to get the armor removed in doing so, but neither of us were ever truly gone. You see, when you first put the armor on and grasped the hilt of the weapon, our artifacts keyed themselves to your unique DNA pattern. In a way, you have been chosen to wield us in battle."**_ the sword spirit explained.

That last bit threw Billy for a loop.

"Battle? What battle?" he asked.

" _ **Perhaps I can best explain."**_ said the armor spirit. " _ **There is another universe in this vast multiverse being manipulated and slowly destroyed by two rogue gods. Corrupt deities who were meant to represent light and darkness. Good and evil. But they were punished and cast out for their arrogance, believing that there is only one way for life to progress. They blamed each other. They selected a world called Remnant, where they would manipulate the inhabitants to fight their war for them, then destroy that world when it was no longer of use to them. And only you can stop them, Billy."**_

"Me? But why not Grim? Or Mandy? Heck, even Irwin?" asked Billy.

" _ **It is because you have a heart that is pure and just, and a drive to protect even those you do not know. And it is for that reason that we grant you our power and transport you to Remnant."**_ Declared the armored spirit.

And so, in a burst of dragon fire, the spirits returned to their artifacts which began to rapidly spin around Billy. It wasn't long before he too was engulfed in dragon fire which sent him up into the sky, traversing through the dimensional barrier into the world of Remnant. It seems the Black Knight is ready to make a comeback.

* * *

 _ ***To Be Continued…***_

* * *

 _ **There's this chapter for you all. Hopefully, it answers all your questions about how Billy was getting to Remnant. Also, I'm going to be redesigning the original Cursed Armor of the Black Knight and posting the artwork. This will also serve as the title page. Unless I create something else for that purpose.**_

 _ **Thank you guys so much for reading. Don't forget to vote on the poll I have in regards to my Zero to Hero story. May the Force be with you, and have a great day.**_


	3. Chapter 3

_**Well, after many sketches and color scheme debates, I think I'm all set with Billy's armor and weapon. Although, he will be gifted with an additional weapon that will add to his defensive abilities later on. And for those of you who are wondering, this story will mostly follow the events of the RWBY universe with some minor alterations. I hope you don't mind. And if you guys want me to do a Reading/Watching the Story kind of thing as a side story for this one, let me know in the review. All of them will be taken into careful consideration. So now, without further ado, here we go.**_

 _ ***I still don't own The Grim Adventures of Billy and Mandy or RWBY!***_

* * *

 _ **Dialogue Key**_

* * *

"Behold, the Accursed Armor of the Black Knight!" = Regular Speech

 _'Why is it accursed?' = Thoughts_

 **"Hey. Hey, what's going on? I can't get the suit off!" = Someone Yelling**

 _ **"Oh, that's why." = Spirits Speaking**_

 _ **-Grim & Evil- = Scene Transition**_

* * *

 _ **Arrival of the Black Knight**_

* * *

The next day in Endsville, a young woman was standing at the bus stop as she waited for her ride to school. This girl is actually someone who Billy used to consider a friend. This girl is Mandy. She has blonde hair that is styled into a set of devil horns held back by a black hairband, blue eyes that are constantly narrowed into a glare, and pale skin. However, it seems that even age was unable to grow her a nose. Her school uniform consisted of a white blouse, a blue skirt that went down to her knees, and a pair of black shoes.

She examined her nails as she got a strange feeling that something was off about the current setting. But she couldn't quite figure out what it was. The sun is shining, no humidity, and no Billy here to contaminate the air with his dorkiness. By all accounts, it should be the perfect day. And yet… she can't shake this feeling that something is going to change in her life. And not for the better.

"I wonder if this is how Grim felt on the day that Billy and I beat him at Limbo for the soul of Billy's pet hamster, Mr. Snuggles?" Mandy thought aloud. "If it is, then chances are my life's about to take a nosedive."

Saying this caused the girl to look to her face where her nose would be. She's always been a little bit self conscious about her lack of a nose, but never really let it bother her until this point. She never really had a reason to until now. There had always been some sort of supernatural event or catastrophe that often seemed to revolve around her and Billy, so she's always been too focused on survival to really care if she had a nose or not. But now that she's a young woman in her junior year of high school, she's a bit more attentive to things like this.

' _Is plastic surgery even an option at this point?'_

"Hey, Beau!" called an annoyingly familiar voice.

' _Oh, I would much rather have Billy here than THIS lovestruck dweeb!'_ Mandy thought as she recognized the voice.

Walking up to her was a slightly obese young man, about her age, wearing the same school uniform that Billy does. The only difference is that he's wearing a red bow tie around his neck. He has short black hair, dark skin that shows his African-American heritage, and he wears black glasses with thick rims.

This is Irwin, Billy's best friend since they were toddlers.

And wouldn't you know it, he's smitten with Mandy to the point of obsession. The blonde's not ignorant. She's seen that shrine he keeps in his bedroom closet. Definitely the second creepiest thing she's ever seen in her life.

"You ready for class today, Mandy?" Irwin asked.

"If by that, you mean ready to be metaphorically bored to death by another one of Miss Budderbee's lame lectures, then yes." Mandy said in her usual monotone.

Both teens had to brace themselves as the ground beneath them suddenly began trembling as if an earthquake was occurring at this very moment. But they both know better. This was simply the arrival of Billy's cousin, who just so happens to literally live in the center of the Earth. Rising up from the ground, a giant drilling machine broke through the Earth's crust, still steaming from both friction and the head from the planet's magma core.

A door opened up in the vehicle's canopy to reveal a small balcony where a man made of black energy or tar, and a seventeen year old boy with pale skin, slicked back black hair, and brown eyes with green sclera wearing glasses and the standard boy's uniform for Endsville High School. These two are Nergal and his son, Nergal Junior. Just call the lad Junior. Everyone does.

"What a glorious day for school! Right, son?" Nergal said with joy.

"Right, Dad." smiled Junior, revealing a mouth full of sharp green teeth.

"Good luck on your history exam today." Nergal said to his son, clapping him on the back.

Unfortunately, this sent the lad plummeting to the cold, hard, unforgiving ground below as he screamed from the fall.

"Incoming!" said Mandy.

She and Irwin weren't really all that concerned. This kind of thing happens so often, they were used to it. All they had to do was sidestep the falling boy, and he hit the ground flat on his head. The boy opened his eyes with a bit of difficulty due to the pain from the initial impact, but eventually, he was able to make out the image of Mandy looking down on him.

"Nergal Junior." she said casually.

"Hey, guys. What's up?" Junior greeted.

"Bye, son!" Nergal said with a wave.

With his mission to drop off his son complete, the tar man retreated back into the center of the Earth, ready to get things done. Like refurbishing the kitchen for his and his wife's upcoming anniversary.

"Hey, aren't you guys short one Billy?" Junior asked.

"Yeah, I've been meaning to ask about that. Where is he?" Irwin asked before adding "He's always the first one here."

"Last I heard, Spurg and his goons did a real number on him yesterday and got arrested for it. Chances are his injuries are just slowing him down. Billy will be back on his feet in no time." Mandy said dismissively.

As the blonde girl began to walk to school, no longer having the patience to wait for the bus, Irwin and Junior shared a look. They both had a feeling that Billy wouldn't be showing up again any time soon. Oh, if they only knew how right they are.

 _ **-Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil- -Grim & Evil-**_

It was initiation day at Beacon Academy, and the students were getting ready to be launched into the Emerald Forest in order to find their relics and for a team of four applicants. And so far, all but one were feeling confident about being launched into a forest full of deadly Grimm. But before anyone could be launched, Ruby Rose, a fifteen year old girl with short dark brown - almost black - hair that faded to dark red at the tips, silver eyes, and pale skin, wearing a black and red outfit that kind of resembles the fairytale character Red Riding Hood, noticed something falling out of the sky.

"What's that?" she asked, pointing to the sky.

"What's what?" asked the Headmaster of Beacon in return as he looked in the general direction his possible student was pointing.

The man in question is known as Ozpin. He himself looks like a middle-aged man with messy silver gray hair and black eyebrows that suggest his hair must have been black at some point. He wears shaded glass spectacles and a small, purple, cross-shaped pin on the cowl around his neck. His outfit mainly consists of an unzipped black suit over a dark green, buttoned vest and green shirt. He also wears black trouser shoes and long, dark-green pants. In addition to his cane, his other frequent accessory is a mug bearing the Beacon Academy emblem, from which he drinks hot cocoa.

Ruby pointed at the sky, causing both Ozpin and his assistant Glynda to follow the girl's line of sight and see exactly what she saw. It was a green ball of flame falling right out of the sky towards the Emerald Forest. Whatever it was must've been quite powerful, because when this fireball made landfall, it caused a tremor so strong that it almost knocked the students off of the cliff and to their doom.

Fortunately, everyone was able to keep their footing and not fall to their untimely and possibly comical deaths. But it did leave everyone flabbergasted by what happened.

"What was that!?" yelped a girl with orange hair and cyan eyes.

"Why was the fire green?" a boy with black hair with a magenta stripe and pink eyes asked.

"Anybody hurt?" asked a concerned blonde boy.

Ozpin looked at Glynda and the blonde teacher gave her boss a subtle nod. They could both feel it. There's something supernatural within that fire. Something that hasn't graced their world since the time before time. It would seem that the armor and blade of a certain knight have found themselves a new wielder. And they have brought that person to this realm for a purpose.

They'll have to be vigilant and maybe send Qrow to that neck of the woods to try and figure out just what kind of skill this new warrior has. But it will have to wait. They must first get through Beacon's initiation and establish who will be placed into teams.

* * *

 _ ***To Be Continued…***_

* * *

 _ **Before I officially end the chapter, I have a few questions for everyone. If you wouldn't mind answering them to the best of your abilities, that would be most helpful.**_

* * *

 _ **1.) If you were there when Billy overheard his mother's plans to make him leave Endsville and force him into military school, what would you say to Billy to help him?**_

 _ **2.) How long should it be before Grim manages to find where Billy's gone and go after him with Mandy?**_

 _ **3.) Should Billy eventually forgive his parents? (I say parents because while his dad didn't agree with his wife's choices regarding Billy, he didn't try to argue with her either. Or stand up for his son.)**_

 _ **4.) Do you guys want Billy's sword to mechashift into a long range weapon? And if so, what sort of weapon do you want it to shift into?**_

 _ **5.) Would you like me to do a Reading/Watching the story for this one?**_

 _ **6.) And finally, do you want Billy to be turned into a Faunus upon his arrival to Remnant? If so, what kind of animal traits do you want him to have?**_

* * *

 _ **Thank you guys so much for reading. Don't forget to answer my questions and leave a long review. May the Force be with you, and have a great day.**_


End file.
